text: (function(app, owl) {
      class AppView extends owl.View {
          constructor() {
              super({
                  el: document.querySelector('html')
              });
              // update links to data-element
              // and update special events (submit, focus, blur)
              this.update();
          }
  
          showMain(view) {
              this.elements.main.style.display = 'block';
              this.elements.error.style.display = 'none';
              this.elements.main.innerHTML = '';
              this.elements.main.appendChild(view.getEl());
          }
  
          showError() {
              this.elements.main.style.display = 'none';
              this.elements.error.style.display = 'block';
          }
      }
      app.AppView = AppView;
  })(app, owl);